1. Field of the Invention
The present invention relates generally to welding equipment and more particularly to an apparatus and system for providing a multi-function welding and cutting fluid and power supply.
2. Description of the Prior Art
The complexion of the metal fabracating industry has changed substantially in the past few years. In prior times it was relatively rare for smaller metal fabricating shops to become involved in work with more exotic materials such as stainless steel, titainum, copper and other alloys which could not be handled using conventional cutting and welding equipment. For these reasons, even smaller scale fabricating shops are now required to main two separate power sources to provide the capability of carrying on Stick Electrode Welding, Tungsten Inert Gas (TIG) Welding, Plasma Welding and Plasma Cutting. However conventional equipment used for Plasma Cutting is presently extremely expensive and constitutes a relatively high level of investment, particularly for small fabrication shops. Furthermore, since shops of this nature do not continuously work with more exotic materials of the type described above, the expensive conventional plasma cutting and welding equipment is typically not used a good portion of the time, and accordingly investment in such equipment becomes an inefficient use of resources. Thus a need exists for a relatively low cost multi-function unit capable of all modes of welding and cutting, including Plasma Cutting through ordinary Stick Welding.
In order to achieve a system which is capable of performing the many different types of welding and cutting processes described above, it is necessary to provide high voltage capabilities along with many other control facilities for supplying various fluids including gases and cooling water. In the past welding power supplies have been developed which appear similar to the multi-level power system of the present invention, yet are totally incapable of supplying power for both plasma and conventional welding. An example of such a device is disclosed in the Grist patent (U.S. Pat. No. 3,530,359), issued Sept. 22, 1970. This patent discloses a conventional adjustable arc welding power supply system having two rectifier type power supplies connected in parallel. One power supply provides the main welding current, and the other provides a somewhat higher voltage for starting the arc. This arc starting voltage, although higher than conventional welding current supply voltages is a "high" voltage only by reference to the welding supply voltage (e.g. 80 volts versus approximately 40 volts for the welding supply). This somewhat higher voltage auxiliary power supply of the Grist reference is only sufficient for arc starting purposes in a conventional arc welding supply. However, the 80 volt auxiliary power supply is not in any way sufficient to provide the voltage levels required for a sophisticated process such as Plasma Cutting, as this process requires an open circuit voltage on the order of 250 volts. Accordingly, the invention disclosed in the Grist patent is not at all suitable for multi function purposes, but can be used only as a conventional arc welding power supply. Furthermore, the device disclosed in this reference does not have the capability of supplying selected welding gases and cooling liquid.
The present invention is therefore believed to constitute a substantial advance over such previously known welding systems.